Process for manufacturing bulky fabrics

ABSTRACT

A process for producing a bulky fabric which comprises impregnating a fabric with a bound water-containing metal salt, heating the impregnated fabric to expand said metal salt contained in the fabric, heat-setting the resultant fabric and washing with water the resultant fabric to remove the expanded metal salt; said bound water-containing metal salt being expandable by the emission of its own bound water when heated at a temperature of from 100* C. to a second order transition temperature of the fiber to produce the expanded metal salt soluble in water but not melting or decomposing at a temperature applied in said heat-setting step.

United States Patent Inventors Haruo lshida Hirakata-shl; Kiyoshi Otaka,Hyogo-ken, both of Japan Appl. No. 787,237 Filed Dec. 26, 1968 PatentedNov. 23, 1971 Assignee Daiwa Chemical Industries Ltd.

Osaka-shi, Japan Priority Dec. 29, 1967 Japan 42/84829 PROCESS FORMANUFACTURING BULKY FABRICS 2 Claims, No Drawin U.S. Cl. 117/62, 1 17/ 139.5 CE

Int. Cl 844d l/44 Field of Search 1 17/62,

1 [56] References Cited UNlTED STATES PATENTS 758,311 4/1904 Goldman106/150 Primary Examiner-William D. Martin Assistant Examiner-M.Sofocleous An0rney--Larson, Taylor and Hinds ABSTRACT: A process forproducing a bulky fabric which comprises impregnating a fabric with abound water-containing metal salt, heating the impregnated fabric toexpand said metal salt contained in the fabric, heat-setting theresultant fabric and washing with water the resultant fabric to removethe expanded metal salt; said bound water-containing metal salt beingexpandable by the emission of its own bound water when heated at atemperature of from 100 C. to a second order transition temperature ofthe fiber to produce the expanded metal salt soluble in water but notmelting or decomposing at a temperature applied in said heat-settingstep.

PROCESS FOR MANUFACTURING BULKY FABRICS This invention relates to bulkyfabrics such as bulky woven and knitted fabrics and the manufacturethereof. More particularly, the invention pertains to a novel processfor manufacturing bulky fabrics and a novel intermediate fabrics forpreparing bulky fabrics.

In general, bulky fabrics are prepared in the prior art by weaving bulkyyams into a textile fabric and heat-setting it. ln the heat-settingprocess temperatures higher than second order transition temperature ofthe fibers constituting the fabric are usually applied to heat-set thefabric. When fabrics of synthetic fibers which are heat-shrinkable areheated at such high temperatures, however, undesirable shrinkage of thefabrics occurs to the extreme degree, making it difficult to producefabrics having excellent bulkiness, softness, hand the the likecharacteristics. While lengthwise and widthwise shrinkage of the fabriccan be prevented to some extent by using a tenter or other mechanicalmeans, it is inevitable that the extreme shrinkage occurs in thicknessof the fabric, reducing the thickness of the fabric and resulting in theproduct hard to the touch.

Further, the creases produced in the fabric during dyeing and finishingsteps have so far been removed by ironing, pressing or tentering, but insuch a case some shrinkage of the fibers is unavoidable. To prevent thecreation of the creases dyeing and finishing of bulky fabrics havebeendone in the prior art using special machines such as beam dyeingmachine, jet dyeing machine, open-soaper, etc., but the equipment asabove calls for enormous expenditure for installation and operation.

An object of the invention is to provide bulky fabrics having excellentbulkiness, softness, hand, shrink-proof property, crease-proof property,pleating property and draping property.

Another object of the invention is to provide a process formanufacturing bulky fabrics having above characteristics free from thedrawbacks of the conventional processes.

A further object of the invention is to provide expanded fabricsresistant to heat applied in the heat-setting step and capable ofproducing bulky fabrics having above characteristics free from undesiredshrinkage.

The above and other objects and advantages of the invention will beapparent from the following description.

According to the researches of the present inventors, it has been foundthat when a woven or knitted fabric is impregnated with a certain kindof bound water-containing metal salts and heated at a temperature notlower than l C. to expand the metal salts, a unique expanded fabriccontaining expanded metal salts interposed in the intervals betweenfibers of the fabric can be obtained and that when such an expandedfabric is subjected to a heat-setting step, such fabric is set in theexpanded form without showing any shrinkage and a bulky fabric havingexcellent properties is produced after the removal of the expanded metalsalts contained therein.

The fabrics used in the invention include woven fabrics and knittedfabrics prepared from at least one of synthetic fibers which areheat-shrinkable. Examples of the synthetic fibers are polyester,polyamide, polyacrylonitrile, polyurethane, polyvinyl chloride,polypropylene and the like fibers. Further, the fabrics made of mixedyarn of said synthetic fibers and natural or semisynthetic fibers, andthe fabrics in which the yarn of said synthetic fibers and that ofnatural or semisynthetic fibers are combined can also be used in theinvention.

The bound water-containing metal salts used in the invention should haveproperties expandable by the emission of their own bound water whenheated at a temperature of from 100 C. to below a second ordertransition temperature of the fibers constituting the fabric to producethe expanded metal salt soluble in water but not melting or decomposingat an elevated temperature applied in the heat-setting step, i.e., atemperature of a second order transition temperature to below adecomposing temperature of the fibers. In the invention various metalsalts having above properties can be used, which include organic metalsalts, inorganic metal salts, double salts and complex salts. Typicalexamples of such metal salts are hydrous calcium chloride (CaCl 'l-l oor CaCl '6H-, 0), hydrous sodium tetraborate (Na B,Q 'l0H O), hydroussodium acetate (CH -,COONa-3H,O), hydrous aluminum sulfate [Al (SO l8HO], hydrous aluminum potassium sulfate [KAI (SO 'l2H O], hydrousmagnesium chloride -(MgCl 6I-l O), hydrous sodium potassium tartrate (K-NaC H4OO6 41-1 0), hydrous sodium thiosulfate (Na i S 0 SH O), hydroussodium silicate (Na2O XSiO2'yH20), ydrous sotmlrn metasilicate (l l a Si Q 5l-l O) etc. V 7

When these metal salts are heated at a temperature of higher than C.,they are first dissolved in their own bound water and emit the water ina gaseous state to produce pumicelike expanded solids of the metal saltswhich are soluble in water but can not be melted nor decomposed at anelevated temperature to be applied in the setting step of the fabric.The expanded volume of the metal salts may vary depending on the kind ofthe metal salts used and the heat conditions to decompose the metalsalts. Preferable heat conditions are represe nte d in the Table 1below, in which expanded volume is determined by the following equation.

Volume of metal salt expanded Expanded volume 100 containing inetal saltused A The metal salts can be used alone or in mixture and in the formof solution, suspension, paste or powder, and various additives may beadded thereto, as required. For example, to adjust the blowingtemperature, expanded volume and mechanical strength of the expandedsolids, there may be added the conventional blowing agents which willemit carbon dioxide gas, ammonium gas, nitrogen gas, etc., by thedecomposition thereof when heated. For the same purposes as abovefillers, such as metal salts containing no bound water, clay, bentonite,etc., may be added. To improve the stability of the resultant foamsurface active agents or starch paste may be added thereto. Further,dyestuffs may also be added to make it possible to dye the fabricsimultaneously.

According to the invention fabrics are first impregnated with the metalsalts by various means according to the forms of metal salts used, forexample, by dipping, padding, coating, spraying, printing, sprinkling,etc. To obtain bulky fabrics having uniform bulkiness throughout thefabric the entire part of the fabrics may be uniformly impregnated withthe metal salts, while to obtain bulky fabrics having bulky spots andother bulky patterns the fabrics may be partly impregnated with themetal salts in accordance with the patterns desired. The amount of themetal salts infused into the fabric may be in the range of 2 to 200weight percent, preferably 20 to 60 weight percent, based on the weightof the fabric. Throughout the specification and claims the expressionweight of the fabric" is intended to mean the weight of the fibersconstituting the impregnated part of the fabric. Lesser amount of theimpregnation results in poorer effect and higher amount brings noincrease in the effect. rendering the process uneconomical. Thebulkiness of the final bulky fabric may vary depending on the amount ofthe impregnation, so that by suitably selecting such amount the bulkyfabric having desired bulkiness is obtainable.

The fabrics thus impregnated with metal salts are then subjected toheating step to expand the metal salt after squeezing and/or drying, asrequired. When dyestuff is used in combination with the metal salts itis preferable to dry the impregnated fabric prior to the heating step toprevent the migration of the dye. The heating step for expanding themetal salts is carried out at a temperature not lower than I C. butbelow second order transition temperatures of the fibers constitutingthe fabric. Preferable temperatures to be applied may vary in accordancewith the kind of the metal salts and fabrics used, and temperaturespreferable for the respective metal salts are shown in the foregoingtable I. The time required for the expansion of the metal salts may varydepending in the temperature applied and metal salts used. but usually aperiod of 0.1 to minutes is sufficient for the purpose.

The resultant fabric contains expanded metal salts interposed in theintervals between fibers of the fabric and easily soluble in water butnot melting or decomposing by the heat applied in the subsequentheat-setting process. By the presence of the expanded metal salts thefabric thus obtained is in expanded form. in more detail the respectivefibers constituting the fabric are elongated irregularly by theexpansion of the metal salts and locked in such conditions by theexpanded metal salts. Accordingly, when the expanded fabric is heated ata temperature higher than a second order transition temperature of thefibers the fabric is heat-set without the shrinkage of the fibers lockedwith the expanded metal salts. The amount of the expanded metal saltsinterposed in the fabric may be in the range of l to I00 weight percent.preferably 10 to 30 weight percent. based on the weight of the fabric.

The bulky fabrics of the invention are prepared by heatsetting theexpanded fabric and washing the heat-set fabric with water to remove theexpanded metal salts therefrom. The heat-setting treatment is carriedout in the conventional manner. for example, by heating the expandedfabric at temperatures of second order transition temperatures to belowdecomposing temperatures of the fibers constituting the fabric. Thepreferable temperatures may vary in accordance with the kind of thefibers. but temperatures of not higher than 50 C. above the second ordertransition temperature of the fibers may usually be applied. The timerequired for the heatsetting is usually ().l to 10 minutes. in this stepthe fabric shows no shrinkage as the fibers are locked with expandedmetal salts.

The fabric thus heat-set is washed with water to remove the expandedmetal salts. whereby the bulky fabric having excellent bulkiness.softness. hand, shrink-proof property. creaseproof property. pleatingproperty and draping property is obtained.

In the preferred embodiment of the process of the invention. the heatingstep for expanding metal salts and heatsetting step are carried out in asingle heating apparatus. such as air oven and the like. For example.the fabric impregnated with metal salts is introduced into an air oventhrough which air heated at a temperature of higher than a second ordertransition temperature of the fibers is passed. At the initial stage.while the fabric has not been heated yet to a second order transitiontemperature or higher. the metal salts have expanded, and when thetemperature of the fabric reaches the second transition temperature orhigher. the fabric is heat-set. in a continuous manner the fabricimpregnated with the metal salts is continuously passed through the airoven. and at the inlet portion of the oven the metal salts are expanded.and then the fabric is heat-set.

For better understanding of the invention examples are given below inwhich all parts are in parts by weight.

EXAMPLE 1 A woven fabric of polyester yarn in which creases occurredduring carrier dyeing process using a dispersed dye was immersed in thefollowing composition and squeezed with a mangle to weight percentimpregnation with the composition. based on the weight of the fabric.

"Kciso N0. 3"

(Hydrous sodium silicate containing 60 weight percent of water.specified in JlS K-MOK I966) 50 parts Polyethylcneglycol nonylphenylother 0.5 parts Water 49.5 parts Then the fabric was tentered on a framewith pins to accurate lengthwise and widthwise measurements and placedin an air oven heated at C. for 3 minutes. in the first one minute thesodium silicate expanded. generating water vapor and in the last twominutes the fabric was heat-set. Thereafter the fabric was washed withwater to remove the expanded metal salts and dried at 80 C. Thus thebulky fabric having the properties shown in table 2 below was obtained.

For comparison. the same treatment was performed using the compositionsame as above but not containing hydrous sodium silicate. The resultsare shown in Table 2 below.

TABLE 2 Changes in thick- Changes in hand ness Greases Fabric finishedSoftrtess and Nil Completely accordmg to the hand improved. removed.method of the invention.

Comparative iabric Hand hardened Decrease Originally creased and featureof of 30%. portions redrapery lost. mained as depressions.

EXAMPLE 2 A woven fabric of polyamide yarn was impregnated with thefollowing composition in the order of 50 weight percent impregnation anddried at room temperature.

Hydmus aluminum potassium sulfate 40 parts Bentonilc (water content. Xi)uuighl percent) 10 arts Water 50 parts TABLE 3 Changes in thick- Changesin hand ness Pleat Fabric finished softness and Nil Excellent pleats.

by method of the hand improved. invention.

Comparison Hand hardened... Decrease Pleated portions of 40%. thinnedand sharpened and partly shrunk.

EXAMPLE 3 A woven fabric of bulky polyester yarn was immersed in thefollowing composition, squeezed with a mangle to 80 weight percentimpregnation and dried at 60 C.

"Foron Blue BL" (Trade Mark. Sandoz Ltd., Switzerland) 4 parts Hydrouspotassium tartarate 30 parts Carboxymethyl cellulose l parts Sodiummetanitrotuluenc sulfonat: 1 parts Polyethyleneglycol l nonylphenylother 0.5 parts Water 63.5 parts The fabric thus treated was tentered ona frame with pins and placed in an air oven heated at 180 C. forminutes. in the first 1.5 minutes the hydrous sodium potassium tartarateexpanded, generating water vapor and in the last 3.5 minutes the fabricwas heat-set. The removal of the expanded metal salts by washing withwater gave the bulky fabric having the properties shown in table 4below. 5

For comparison the same treatment was performed using the samecomposition as above but not containing hydrous sodium potassiumtartarate. The results are shown in table 4 below.

TABLE 4 Changes Changes in in hand Dyeing property thickness Sampletreated 50- softness Excellent Nil.

cording to the and hand method of invenimproved. tion.

Comparison Hand Excellent. Sli htly Decrease of hardened. derkerin coour 32%.

due to shrinkage of fibers.

EXAMPLE 4 A textile fabric of high-bulky polyacrylonitrile yarn, inwhich creases were created during dyeing process was immersed in thefollowing composition, squeezed with a mangle 4 to 80 weight percentimpregnation and dried at 60 C.

Hydrous sodium acetate 30 parts Hydrous sodium formate partsPolyethyleneglycol nonylphcnyl ether 0.5 parts Water 49.5 parts TABLE 5Change Changes in in hand thickness Crease ;Samp1e finished acsoftnessNil Completely cording to the and hand removed. method of the improved.invention.

Comparison Hand Decrease of 35%"... Originally hardened creased 1 andfeaportions ture of remained drapery as depresdecressed. sions.

EXAMPLE 5 A textile fabric of polyester yarn in which creases occurredduring dyeing step was immersed in the following composition 5 andsqueezed with a mangle to I00 weight percent impregnatron.

Hydrous aluminum sulfate 25 parts Hydrous sodium thiosulfate 25 partsPolyethylcncglycul nonylphenyl ether 0.5 parts Water 49.5 parts Thefabric thus treated was tentered on a frame with pins and placed in anair oven heated at l C. for 3 minutes. In

5 the first one minute the metal salts expanded, generating water vaporand in the last two minutes the fabric was heatset. The removal of theexpanded metal salts gave the bulky fabric having the properties shownin table 6 below.

For comparison. the same treatment was performed using the samecomposition as above but not containing hydrous aluminum sulfate andhydrous sodium thiosulfate. The results are shown in table 6 below.

TABLE 6 Change Change in in hand thickness Crcasos Bulky fabric of thesoftness Increase (omplctoly removed.

invention. and hand of 5%.

improved.

Comparison H Decrease of Originally creased portions remained andhardened. 20%.

as depressions.

EXAMPLE 6 Hydrous sodium metasilicate powder was uniformly sprinkled ona woven fabric of bulky polyester yarn in the order of 40 weight percentbased on the weight of the fabric and placed in an air oven heated atI80 C. for 5 minutes.

in the first l.5 minutes the hydrous sodium metasilicate was melted,infused into the fabric and then expanded. generating water vapor, andin the last 3.5 minutes the fabric was heatset.

Thereafter the fabric was washed with water to remove the 50 expandedmetal salts and dried, whereby the bulky fabric soft to the touch wasobtained.

EXAMPLE 7 A woven fabric of polyester fiber dyed by carrier dyeing wasimmersed in the following composition prior to heat-treatment forremoving carrier, squeezed to 80 weight percent impregnation and driedat C.

Hydrous calcium chloride 30 parts Hydrous magnesium chloride 20 partsPolyethylencglycol nonylphenyl ether 0.5 parts Water 49 5 parts Thefabric thus treated was placed in an air oven heated at C. for 3minutes. in the first one minute the hydrous calcium chloride andhydrous magnesium chloride expanded, generating water vapor and in thelast two minutes the fabric was heat-set. The fabric was then washedwith water to remove the expanded metal salts and dried at 60 C. Thus,the bulky fabric having the following properties shown in table 7 wasobtained.

For comparison. the same treatment was performed using the samecomposition as above but not containing hydrous calcium chloride andhydrous magnesium chloride. The hydrous sodium potassium tartrate,hydrous sodium resultsare shown in table7below. thiosulfate, hydroussodium silicate and hydrous sodium TABLE 7 Changes in Changes in Removalof hand thickness Greases carriers Fabric of the softness Nil NilCarrier completely invention. and hand removed.

improved. Comparison Han Decrease of Originally Carrier slightlyhardened. 25%. creased remainlng.

portions remained as depressions.

EXAMPLE 8 A woven fabric of polyester yarn was immersed in the followingcomposition, squeezed to 70 weight percent impregnation and dried at 80C.

Hydrous sodium tetraborutc 40 parts Polycthyleneglycul nonylphenyl ether0.5 parts Starch 8 parts Water 5 LS parts The fabric thus treated wastentered on a frame with pins and placed in an air oven heated at 180 C.for 3 minutes. In the first 1 minute the hydrous sodium tetraborateexpanded. generating water vapor and in the last 2 minutes the fabricwas heat-set. The fabric was then washed with water to remove theexpanded metal salts and dried at 80 C. Thus, the bulky fabric soft tothe touch was obtained.

What we claim is:

metasilicate, heating the impregnated fabric to a temperature of froml00 C. to below a second order transition temperature of the fibersconstituting the fabric to expand said metal salt contained in thefabric, heat-setting the resultant fabric at a temperature ranging froma second order transition temperature to below a decomposing temperatureof the fibers and washing with water the resultant fabric to remove theexpanded metal salt; said bound water-containing metal salt being firstdissolved in its own bound water and emitting the water in a gaseousstate when heated at a temperature of from C. to a second ordertransition temperature of the fibers to produce pumicelike expandedsolid of the metal salt soluble in water but not melting or decomposingat a temperature applied in said heat-setting step 2. An expandedsynthetic fabric resistant to heat-shrinkage for producing a bulkyfabric which comprises a fabric and 10 to 30 weight percent, based onthe weight of the fabric, of expanded metal salts interposed in theintervals between fibers of the fabric and water-soluble but not meltingor decomposing at a temperature of between a second transitiontemperature and below a decomposing temperature of the fabrics. saidmetal salts being at least one species selected from the groupconsisting of calcium chloride, sodium tetraborate, sodium acetate,aluminum sulfate, aluminum potassium sulfate, magnesium chloride, sodiumpotassium tartrate. sodium thiosulfate, sodium silicate and sodiummetasilicate.

2. An expanded synthetic fabric resistant to heat-shrinkage forproducing a bulky fabric which comprises a fabric and 10 to 30 weightpercent, based on the weight of the fabric, of expanded metal saltsinterposed in the intervals between fibers of the fabric andwater-soluble but not melting or decomposing at a temperature of betweena second transition temperature and below a decomposing temperature ofthe fabrics, said metal salts being at least one species selected fromthe group consisting of calcium chloride, sodium tetraborate, sodiumacetate, aluminum sulfate, aluminum potassium sulfate, magnesiumchloride, sodium potassium tartrate, sodium thiosulfate, sodium silicateand sodium metasilicate.